In the field of offshore technology, more specifically, in connection with so-called torque tongs or power tongs which are utilized when making up drill strings used to drill wells in search of hydrocarbons (oil and gas), it is usual to use such tongs to screw together/unscrew joints of drill pipe. These tongs are also referred to as iron roughnecks. Usually, an upper pipe part is held by a gripping device, while a lower pipe part is set in rotation by a power tong/torque tong. Another solution uses a so-called slips in the drill floor, and optionally a lower power tong, to hold a lower pipe string in position relative to an upper pipe string that is rotated using a rotary device such as a torque tong, a drilling machine, or the like. The torque tong consists of a jaw which has dies. The task of the dies is to hold the pipe firmly in the torque tong and to prevent rotation of the pipe during its assembly with other pipes. The dies are therefore subjected to substantial forces and must be replaced at regular intervals due to wear. An example of an iron roughneck is described in NO 319959 B1 where a die is mounted on each of three displaceable clamping devices. The die is equipped with a plurality of relatively sharp ridges that are clamped against the pipe wall and thus grip it.
NO 20092552 describes a replaceable die for torque tongs/power tongs. A holding means for a die is described comprising a body having longitudinal grooves with internal walls for contact with corresponding surfaces on the die, where a first wall is movable between a retracted position in the groove in which the die is released and an advanced position in the groove in which the jaw is gripped in contact with the internal walls. It is further described that the first wall comprises an outer surface on a wedge-shaped element with a first face inclined relative to the first wall and arranged on an opposite side of the first wall, and where the first inclined face is in contact with an opposing and corresponding second inclined face. A relative movement between the first and second inclined faces causes the first wall to move between the corresponding retracted and advanced positions. The groove itself is thereby configured as a wedge in which a mounted wedge-shaped element is placed.
The groove and the die must be configured with a minimum of play so that the die sits firmly in the groove. This is not necessarily compatible with the harsh environment in which the device is operated, i.e., an environment with a great deal of pollution from oil, dirt, dust etc., which can result in the small clearances in the groove becoming blocked and the die becoming jammed. This can lead to the dies sticking when they are to be replaced, which results in an increased expenditure of time.
Prior art dies therefore have a tendency to become jammed and can be difficult to replace when they are worn.
A need therefore exists to provide an improved device to replace dies which remedies or reduces at least one of the disadvantages of the prior art.